Porphyria is most often an inherited mutation in one of the genes involved in heme production, although environmental factors can trigger symptoms in some cases.

Heme is a major component of hemoglobin, the protein in red blood cells that carries oxygen from your lungs to all parts of your body. Heme also plays a role in breaking down chemicals so they can be removed from your body. Heme is made mainly in the bone marrow and liver through the production of porphyrin and linkage with iron.

Eight different enzymes add and convert natural, smaller building blocks into porphyrin, which becomes heme with the addition of iron. Deficiency of a specific enzyme that's involved in the body's process for making heme can result in the buildup of porphyrins, causing symptoms. Each type of porphyria is due to the deficiency of a different enzyme.

Genetics

Most forms of porphyria are inherited. Porphyria can occur if you inherit:

  • A defective gene from one of your parents (autosomal dominant pattern)
  • Defective genes from both parents (autosomal recessive pattern)

Just because you have inherited a gene or genes that can cause porphyria doesn't mean that you'll have signs and symptoms. You might have what's called latent porphyria, and never have symptoms. This is the case for most carriers of the abnormal genes.

May. 20, 2014

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